The present invention relates to a detector for providing an effective means for non-invasively monitoring the perfusion ratio which is an indication of the efficiency of the perfusion of blood by external cardiac massage during a cardiac arrest. The device described herein is also particularly adapted to provide an immediate feedback to the person providing cardiopulmonary resuscitation (CPR) as to the efficacy of the external cardiac massage (ECM) as indicated by the ratio of the perfusion period to the period of the (ECM).
There have been many endeavors to improve the techniques associated with the management of cardiac arrest. The development of electro-cardiograph (ECG) equipment enables doctors to observe, through non-invasive means, the electrical activity of the heart. This provides valuable information for the diagnosis and treatment of various cardiac problems. Lightweight, battery powered (ECG) recorders have been developed to provide field deployment capabilities. The development of the cardiac defibrillator is also important especially in the treatment of certain electrical problems of the heart, and has also been designed to travel with emergency teams into the field. The potential danger associated with the defibrillator, however, has limited use basically only to those people under the direct supervision of a physician. The development of the modern technique of cardio-pulmonary resuscitation (CPR) has proved to be an effective means of managing the cardiac arrest patient in lieu of more sophisticated techniques, and equipment associated with a hospital trauma center or operating room. (CPR) makes use of external cardiac massage (ECM) to perfuse the patient's blood by compressing the heart between the sternum and the spine. The person administering the (ECM) is required to push quite hard and also sufficiently long on the patient' s chest to move the bllod throughout the patient's circulatory system. Research by many investigators, outlined hereinafter, has indicated that the ratio of the period of blood perfusion time to the period of the (ECM) is a critical factor in providing an adequate blood supply to the patient's brain. However, the efficacy of (ECM) is difficult to monitor non-invasively. One common indication of efficacy is the dilation of the pupils, indicating inadequate perfusion to the brain and probable brain damage. Clearly this is not an effective indicator. Thus, the purpose of the device of the present invention is to provide an immediate feedback as to the efficacy of the (ECM) as indicated by the ratio of the perfusion period to the period of the (ECM).